Fundamental Research And Application Of Triboelectric And Piezoelectric Hybrid Nanogenerator

Triboelectric nanogenerators and piezoelectric nanogenerators are widely studied and used in collectting environmental vibration energy field.These nanogenerators have a broad prospect in sovling nenergy crisis in the future.βphase polyvinylidene fluoride（PVDF）,hexagonal wurtzite phase GaN and tetragonal barium titanate（BaTiO₃）have been used in piezoelectronic devices for their excellent piezoeletric property.Polydimethylsiloxane（PDMS）has been used as triboelectric material to design triboelectric nanogenerators.In this thesis,we have successfully ingtegrated triboelectric and piezoelectric effect in one matrial like PVDF film,GaN/PDMS composite film or BaTiO₃/PDMS composite film to design trioelectric and piezoelectric hybrid nanogenerators for the first time.The effect of experimental process on the output of the hybrid nanogenerators was systemically invesitigated.It isdemonstrated that triboelectric nanogenerator can be used in the electrical deposition process for the growth of nanostructure mataerials such as nickel hydroxide nanostructures for the first time in our study.（1）.The triboelectric and piezoelectric hybrid nanogenerators using piezoelectric PVDF film as piezoelectric part and its surfaceas triboelectric part were designed and constructed.The effect of polarization condition on the output of the hybrid triboelectric nanogenerator was invetigated.It is shown that forward poling or reverse poling could enchance the output voltage and current density with 1.3 V and 1.2 μA/cm2,or decrease the output voltage and current density with 1.2 V and 1.8 μA/cm2,respectively.By spin-coating PDMS film onto the PVDF film could enhance the output voltage and curent density with 1.9 V and 1.9 μA/cm2.By controlling the’ thickness of the PVDF film in the PDMS/PVDF composite film,the output power of the hybrid nanogenerator could be controlled.The output power increased with the thickness of PVDF film increasing.When the thickness of PVDF film increased to 40 μm,the output voltage and current density were 8.4 V and 7.7μA/cm2,respectively.（2）.Three dimensinal GaN nanostructures and one dimensional polar surface dominated GaN nanostructures with zigzag morphology were sucessfully synthesized using simple chemical vapor deposition method.The morphology and crystal structures of the as-prepared GaN nanostructures were charaterized by scanning electron microscopy（SEM）,transmissionelectron microscopy（TEM）,X-ray diffraction（XRD）and Ramanspectroscopy.By mixing piezoeletric GaN particles with PDMS together,GaN/PDMS composite films were synthesized.Hybrid nanogenerator was developed using GaN’s piezoelectric effect and PDMS sufrace with triboelectric effect.The influence of GaN mass ratio in GaN/PDMS composite films on the output of the hybrid nanogenerator was studied.The output of the hybrid nanogerator increased with GaN content increasing.When GaN mass ratio increased to 9 wt%,the output voltage and current density got the highest values of 9.5 V and 10.9 μA/cm.With GaN contentfurtherincreasing,the output performance of the hybrid generator decreased.When GaN content increased to 20 wt%,the output voltage and current density decreased to 7.0 V and 7.5 μA/cm.（3）.By mixing piezoeletric BaTiO₃ nanoparticles with PDMS together,BTO/PDMS composite films were prepared.Hybrid nanogenerator was developed using BTO’s piezoelectric effect and PDMS sufrace’s triboelectric effect.By poling the composite film under forward or reverse direction,the output power density of the hybrid nanogenerator couldbe increased or decreased.For 200μm thickness and BTO content with 20 wt%,forward poling and reverse poling could increse and decrease the output voltage with 4.3 V and 3.4 V,respectively.The effect of the BTO mass ration in the BTO/PMDS composite film on the output was investigated.When the BTO mass ratio increased into 20wt%,the output performance of the generator got the best.In addition,the influence of film thickness on the output was also studied.100 μm thickness films have higher output than that of 200 μm thickness films.Moreover,three test modes were designed to distinguish the piezoelectric and triboelectric output.The hybrid mode.triboelectric and piezoelectric output voltages were 3.3 V,2.2 V and 1.1 V,respectively.These two contributions could be added up to enhance the hybrid generator’s output power.Finally,the three test modes were used to charge a 2.2μFcapacitor and the hybrid mode exhibited the best performance.The hybrid mode reached its saturationvoltage（～1.44 V）most rapidly wthin 50 s.（4）.A simple triboelectric nanogenerator based on contact-detact mode was constructedand applied into electrodeposition of materials.By comparing the output under different mechanical vibration frequencies,the frequency of 1 Hz mecahical vibration was chosen as force source of the generator for electrodepositon.Nickel hydroxide nanostructures were successfully electrodeposited onto different substrates includingFTO glass,FTO glass supported ZnO nanorods arraysand silicon coated with gold filmby using tribeoelctric nanogenrator.The morphology,composition and electrochemical properties were characterized by SEM,X-ray photoelectron spectroscopy（XPS）and cyclic voltammetry（CV）methods.